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        <p>Library Version 11.2.5.3</p>
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          <th colspan="3" align="center">DB_ENV-&gt;set_lk_detect()</th>
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          <td width="20%" align="left"><a accesskey="p" href="envset_lk_conflicts.html">Prev</a> </td>
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            <h2 class="title" style="clear: both"><a id="envset_lk_detect"></a>DB_ENV-&gt;set_lk_detect()</h2>
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      <pre class="programlisting">#include &lt;db.h&gt;

int
DB_ENV-&gt;set_lk_detect(DB_ENV *dbenv, u_int32_t detect);  </pre>
      <p>
         Set if the deadlock detector is to be run whenever a lock conflict
         occurs, and specify what lock request(s) should be rejected.  As
         transactions acquire locks on behalf of a single locker ID, rejecting
         a lock request associated with a transaction normally requires the
         transaction be aborted.
    </p>
      <p>
         The database environment's deadlock detector configuration may also be
         configured using the environment's <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file.  The
         syntax of the entry in that file is a single line with the string
         "set_lk_detect", one or more whitespace characters, and the method
         <span class="bold"><strong>detect</strong></span> parameter as a string; for
         example, "set_lk_detect DB_LOCK_OLDEST". Because the <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a>
         file is read when the database environment is opened, it will
         silently overrule configuration done before that time.
    </p>
      <p>
         The <code class="methodname">DB_ENV-&gt;set_lk_detect()</code> method configures a database environment,
         not only operations performed using the specified <a class="link" href="env.html" title="Chapter 5.  The DB_ENV Handle">DB_ENV</a>  
         handle.
    </p>
      <p>
         The <code class="methodname">DB_ENV-&gt;set_lk_detect()</code> method may be
         called either before or after environment open, but once it is set
         it may not be changed again during the environment's lifetime.
    </p>
      <p>
         The <code class="methodname">DB_ENV-&gt;set_lk_detect()</code> <span>
            <span>
                  method returns a non-zero error value on failure and 0 on success.
            </span>
            
        </span>
    </p>
      <div class="sect2" lang="en" xml:lang="en">
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              <h3 class="title"><a id="idp52477856"></a>Parameters</h3>
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        <div class="sect3" lang="en" xml:lang="en">
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            <div>
              <div>
                <h4 class="title"><a id="idp52487840"></a>detect</h4>
              </div>
            </div>
          </div>
          <p>
                          The <span class="bold"><strong>detect</strong></span> parameter configures the
                          deadlock detector.  The deadlock detector will reject the lock request
			  with the lowest priority.  If multiple lock requests have the lowest
			  priority, then the <span class="bold"><strong>detect</strong></span> parameter
			  is used to select which of those lock requests to reject.  The
			  specified value must be one of the following list:
                     </p>
          <div class="itemizedlist">
            <ul type="disc">
              <li>
                <p><a id="set_lk_detect_DB_LOCK_DEFAULT"></a>
                  <code class="literal">DB_LOCK_DEFAULT</code>
            </p>
                <p>
                 Use whatever lock policy was specified when the database environment
                 was created.  If no lock policy has yet been specified, set the lock
                 policy to DB_LOCK_RANDOM.
            </p>
              </li>
              <li>
                <p><a id="set_lk_detect_DB_LOCK_EXPIRE"></a>
                  <code class="literal">DB_LOCK_EXPIRE</code>
            </p>
                <p>
                 Reject lock requests which have timed out.  No other deadlock
                 detection is performed.
            </p>
              </li>
              <li>
                <p><a id="set_lk_detect_DB_LOCK_MAXLOCKS"></a>
                  <code class="literal">DB_LOCK_MAXLOCKS</code>
            </p>
                <p>
                 Reject the lock request for the locker ID with the most locks.
            </p>
              </li>
              <li>
                <p><a id="set_lk_detect_DB_LOCK_MAXWRITE"></a>
                  <code class="literal">DB_LOCK_MAXWRITE</code>
            </p>
                <p>
                 Reject the lock request for the locker ID with the most write locks.
            </p>
              </li>
              <li>
                <p><a id="set_lk_detect_DB_LOCK_MINLOCKS"></a>
                  <code class="literal">DB_LOCK_MINLOCKS</code>
            </p>
                <p>
                 Reject the lock request for the locker ID with the fewest locks.
            </p>
              </li>
              <li>
                <p><a id="set_lk_detect_DB_LOCK_MINWRITE"></a>
                  <code class="literal">DB_LOCK_MINWRITE</code>
            </p>
                <p>
                 Reject the lock request for the locker ID with the fewest write locks.
            </p>
              </li>
              <li>
                <p><a id="set_lk_detect_DB_LOCK_OLDEST"></a>
                  <code class="literal">DB_LOCK_OLDEST</code>
            </p>
                <p>
                 Reject the lock request for the locker ID with the oldest lock.
            </p>
              </li>
              <li>
                <p><a id="set_lk_detect_DB_LOCK_RANDOM"></a>
                  <code class="literal">DB_LOCK_RANDOM</code>
            </p>
                <p>
                Reject the lock request for a random locker ID.
            </p>
              </li>
              <li>
                <p><a id="set_lk_detect_DB_LOCK_YOUNGEST"></a>
                  <code class="literal">DB_LOCK_YOUNGEST</code>
            </p>
                <p>
                 Reject the lock request for the locker ID with the youngest lock.
            </p>
              </li>
            </ul>
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      <div class="sect2" lang="en" xml:lang="en">
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            <div>
              <h3 class="title"><a id="idp52511608"></a>Errors</h3>
            </div>
          </div>
        </div>
        <p>
                         The <code class="methodname">DB_ENV-&gt;set_lk_detect()</code> <span>
            <span>
                 method may fail and return one of the following non-zero errors:
            </span>
            
        </span>
                    </p>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp52505096"></a>EINVAL</h4>
              </div>
            </div>
          </div>
          <p>
                An invalid flag value or parameter was specified.
            </p>
        </div>
      </div>
      <div class="sect2" lang="en" xml:lang="en">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title"><a id="idp52503008"></a>Class</h3>
            </div>
          </div>
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        <p>
                    <a class="link" href="env.html" title="Chapter 5.  The DB_ENV Handle">DB_ENV</a>, 
                    <a class="link" href="lock.html" title="Chapter 6.  The DB_LOCK Handle">DB_LOCK</a> 
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      <div class="sect2" lang="en" xml:lang="en">
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              <h3 class="title"><a id="idp52506176"></a>See Also</h3>
            </div>
          </div>
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        <p>
                     <a class="xref" href="lock.html#locklist" title="Locking Subsystem and Related Methods">Locking Subsystem and Related Methods</a> 
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